Blue Kid is the second in command/love interest of Mad Saulus and appears in the Violence Jack manga and Violence Jack Evil Town OAV. She wears a S/M leather outfit in the manga and lingure in the anime. She is revealed to be rather smart as she makes strategic decisions that often turn out in her sides favor(such as having a free trade market after Jack is found or knowing that if she...goes xxx on Aila Mu, Mad Saulus won't be mad since he loves her). She is promiscuous and does not mind being with either men or women(and will save a mans life so she can sleep with him later). She is loved Mad Saulus as she does not mind his freakish appearence or fear him. She has an open relationship with him as they both never object to either of them openly mentioning sex with other people. She resembles Gestapoko (the S/M Nazi) from Kekko Kamen episode 1 and it is revealed that she is a hermaphrodite in the manga (which leads to a very unpleasent experience for the leader of section C) (In the anime, she stabs Kawamori before raping Aila Mu.). After (or during) this abuse, Violence Jack comes in and with one swing of his 40cm Jack knife, he slices off her head, left breast and large penis (only Blue's head in the OAV). Mad Saulus returns from his battle with Jack to find his men butchered and Blue dismembered(no pun intended). He weeps for her and swears to take down Jack...then he eats Blue to merge their strength (in the anime, he physically transmogrifies into a huge monster).
There has been some debate on the true gender of Blue. Some say she was born male and became a woman while others say the opposite (though the latter is highly unlikely). Using the manga pages we can see she has a bit of what might be female genitals underneath her rather large male organ. Also when Jack sliced off her left D cup there was blood and no sign of silicone or other breast implants. Furthermore in the anime her big breasts jiggled as though made of real (and soft) breast meat when she jumped when Jack was about to behead her so her big soft bouncy bust is real. It is possible for trans women to develop large breasts through hormone therapy alone. This evidence leads us to feel like she is an hermaphrodite/intersex who was born with the ability to develop breasts and possessing both male and female crotch parts instead of being born one and changed to the other. Blue is likely just an hermaphrodite with both male and female primary sex organs(penis, vagina), but only female secondary sex organs(breasts)